Line-tester



W. H. NISWONGER.

LINE TESTER.

APPLICATION r1120 AUG.25, 1916.

1,321,543. Patented Nov. 11, 1919.

I N V EN TOR. W 1 TN E SSES:

ATTORNEYS.

UNITED STATES PATENT- OFFICE.

WILLIAM H. NISWONG'ER, F BAD AXE, MICHIGAN, ASSIGNOR T0 WILLIAM S. DARLEY, OF CHICAGO, ILLINOIS.

LINE-TESTER.

Specification of Letters Patent.

Patented Nov. 11, 1919.

Application filed August 25, 1916. Serial No. 116,924.

ments in Line-Testers, of which the following is a specification.

My invention relates to improvements in line testers for telephone lines and the like,

and has for its object the provision of a simple and eflicient apparatus of this character for finding short-circuits or grounds in said lines.

The invention consists in the combinations and arrangements of parts hereinafter described and claimed.

The invention will be best understood by reference to the accompanying drawing, which is a diagrammatic view of apparatus embodying my invention, shown as in use.

The preferred form of construction, as illustrated in the drawing, comprises an electric battery 1 preferably in the form of a dry cell, connected in circuit with an ordinary electric push'button 2, a circuit interrupter 3 in the form of an ordinary buzzer or annunciator, and an ordinary condenser 4, all connected in circuit, as indicated, said circuit being provided with readily detachable connections 5 and 6, by means of which the same may be connected with the two wires 7 and 8 of an ordinary double wire metallic telephone circuit. I also provide a low resistance telephone receiver 9 provided with readily detachable connections 10 and 11 by means of which the same may be attached to one of the wires of the telephone line at separated points, as indicated, the telephone receiver preferably having a resistance of about two ohms.

In use, the apparatus is connected up with the telephone, as indicated in the drawing, and we will assume for example that the line is short-circuited at 12 by a wire or other conductor, as indicated. Under this arrangement, upon closing of the circuit from the battery 1, ,by means of the push button 2, a variable or intermittent current will be passed through the telephone wires 7 and 8 owing to the connection therebetween at the point 12. However, the resistance of the telephone receiver 9 being very low and the points 10 and 11 being separated so as to make the resistance between the points 10 and 11 greater than the resistance of the receiver 9, this intermittent current will be caused to pass through the receiver 9 producing a loud intermittent noise therein when held to the ear. If the receiver 9 is connected with the telephone line on the opposite side of the connections 5 and 6, no current will be forced through said receiver inasmuch as the current is passing through the line on the other side of the connections 5 and 6. In this manner the direction of the short-circuit from the point of test may be readily determined. Then the apparatus is moved to a point in the direction in which the short circuit is indicated and a new test made, connecting the receiver on the same side of the connections 5 and 6. If the sound is heard this indicates that the short-circuit is still farther along the line, and if no buzzing sound is heard, it indicates that the short circuit has been passed. In case the short-circuit has been passed the line is tested at a point between the two former tests and the process repeated until the short-circuit is located, as will be readily understood. In case one or the other of the wires 7 and 8 is grounded, one of the connections 5 or 6 is also grounded and the test made as before to locate the ground.

The apparatus may also be used for testing a single wire or return ground circuit by simply grounding one of the terminals 5 or 6 at each test and proceeding as before.

The apparatus set forth is a very simple and efficient one for the purpose, and is capable of economical manufacture.

While I have illustrated and described the preferred form of construction for carrying my invention into effect, this is capable of variation and modification without departing from the spirit of the invention. I, therefore, do not wish to be limited to the precise details of construction set forth, but desire to avail myself of such variations and modifications as come within the scope of the appended claims.

Having described my invention what I claim as new and desire to secure by Letters Patent is:

1. A linemans trouble finder, comprising means for discharging current impulses of high frequency over the line to be tested, and a telephone receiver having means for I connecting the terminals thereof adjustably necting said receiver with said line at septopoints variably spaced apart onone side arated points, substantially as described. ofthe line. 7 r g 5. A line testercomprising a source of 2. A method of ascertaining and locating current; a testing clrcuit including said line trouble which consists in impressing source of current; a double metallic circuit pulsating jvoltage across the line and listento be tested; means for connecting the legs ing on a telephone receiver connectedinof said testing circuit directly with opparallel relationtoa part of one'of the line posite sides of said circuit to be tested; an

conductors. r s interrupter 1n sald testing clrcuit; a telee 3. A line tester comprising means 'for phone receiver of low resistance; and means passing intermittent currents over the line; for directly connecting said telephone reand a low resistance telephone receiver conceiver withone side of said circuit to be v iiected with said line at separated points,. tested at separated points, substantially as .currentga circuit for connectingsaid cursaid receiver having less resistance than the described. line between saidpoints,- substantially as de- In testimony whereof I have signed my scribed. i, V 1 name to this specification in the presence of 4:. A line tester comprising" a source of two subscribing witnesses.

WILLIAM H. NISWONGER.

rent with a line to be tested; aninterrupte'r in, the 'form of a buzzer in said circuit; a push button in said'circuitya telephone receiver of low resistance; and'mean's for'con- Witnesses: Y

lit. HARRIS, I. L. Bonnenss.

v 7 Copies of this patent niay be obtained for five cents each, by addressing the Commissioner of Patents,

L'Washingto'n, D. 0. 

